the control series raxiged from traces to oocaslonally light, while those on 

 the test series vere mostly light or rarely moderate. 



2. Algae . Algae occurred on i|- of the 57 control panels and on 20 

 of the same number of test panels. The growths rated as traces on the panels 

 of the control series, and frcm tracer to light, or rarely moderate, on the 

 panels of the test series . Mo^t of these forms were green algae, hut a 

 hrown alga was noted on one test panel. 



5. Invertehrate animal phyla . 



a. Coelenterata (hydroids ) . Hydroids occurred on 12 control 

 panels and on 5^ test panels. They rated as traces on the panels of the 

 control series, and from traces to light, or rarely mioderate growths, on 

 those panels of the test series. 



h. Bryozoa (encrusting and filamentous ). Encrusting Bryozoa 

 occurred on 7 of the 57 control panels. Electra sp. was identified on one 

 panel. A single colony of a, filamentoas Bryozoa occurred on one of the 

 test panels. 



c. Arthropoda (cirustaceans ). Balanus (harnacles) occiirred on 

 8 of the 57 control panels and on 55 of the same number of test panels. The 

 maximum diameter recorded was 6 mm on the control panels and 19 mm_on a test 

 panel submerged for 8 months. Three of the control panels were from 25^ 



to 70^ covered, and 25 of the test pajiels were from 25^ to 100^ covered. 



d. Mollusca (nonboring mollusks ) . Two specimens of t^ytilus 

 (mussels), 8 mm in length, were recorded on a single test panel. 



A52 . 05 Summary emd Conclusions 



1. Installation . A test hoard of the panel type was operated at 

 the U. S. Naval Operating Base at Dutch Harbor, Alaska, from July 1, 19hh 

 to Augxist 1, 19^7, after which no further panels were received. This base 

 wafl decomissioned on Novemher 1, 19^7. 



2. Test Results . 



a. Borers . Teredinidae occurred to a very limited extent in 

 19^5 and 19^6, the attack rating slight in "both these years; no Teredinidae 

 occvirred in 19^+7 • The breeding season appears to- be limited to the period 

 extending from March through July. Linmoria showed slight evidence of activ- 

 ity throughout the test, but the attack rated only a mere trace each year. 



b. Fouling Organisms . Silt, algae, and invertebrate animals 

 belonging to k phyla contributed to fouling of the panels. The latter In- 

 cluded hydroids, encrusting and filamentous Bryozoa, barnacles, £ind mussels. 



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